Patent GB-374040-A (GB)
Title: Improvements relating to metal-planing and like machine tools
IPC: B23D1/26
Filed: 1931-02-28
Abstract: 374,040. Planing metal strip &c. HEWITT, A., 25, Field Street, King's Cross Road, London. Feb. 28, 1931, No. 6373. [Classes 83 (ii) and 83 (iii).] In a machine for planing or finishing metal strips such as printers' rules the opposite edges of the strip are planed at a single operation by means of oppositely-arranged sets of cutters mounted on a reciprocating head. The frame d carries a horizontal beam c which is substantially of inverted T-shaped cross section and which supports a sliding head b provided with two tool-holders a, one at each side of the vertical web c<1>. The upper face of the web is of approximately the same width as the strip to be operated on and constitutes a supporting surface for the work. The latter is clamped in position by an upper bar e guided in the frame and connected at either end to members f<1> which are eccentrically mounted on a spindle f connected through lever mechanism g .. g<3> to a pedal g<4>. The upper bar e is normally retained in the clamping position by a spring g<6> but when the pedal is depressed the eccentrics f<1> are operated to raise the bar e from the work. Each tool-holder a comprises a transverse slide h which is screwadjusted by means of a graduated head h<1>. The slide h moves transversely over a wedge shaped member i coacting with a second wedge member which may be adjusted to and from the web c<1> for vertical adjustment of the slide h. Each tool-holder is provided with three tools, secured in pairs of tool posts a<1> mounted in the holder a which is readily removed for adjustment of the tools. Any other convenient number of tools may be provided, each tool being separately adjustable so as to distribute the cut. The head b is reciprocated by means of a lead screw k driven through gearing l<1> and reversing bevel gearing m from an electric motor l. The clutch m<3> of the reversing gearing is controlled by a striker bar n carrying dogs n<1> which at the ends of the stroke of the slide b coact with a projection on the slide to reverse the clutch. The reversing gearing may also be controlled by hand from a lever n<2>. Means not described may be provided to release the tools from the work on the return stroke. In order to locate the strip in its correct position, members o extending to the edge of the strip are connected to a lever o<3> whose lower end extends into the path of one of the tool holders so that when the latter is in its starting position the levers o are moved to the position shown in Fig. 2 while when the tool holder moves forward, a spring o<4> removes the levers o from the path of the tools. A stop o<5> may be provided to determine the position of the end of the strip. In a modification, Fig. 3, the beam c is arranged at the top of the machine and the clamping member e is moved upwardly to clamp the strip by springs f<5>. The lead screw k is driven from the motor p through worm reducing gearing p<1>, the motor being controlled by a reversing switch and being associated with a magnetic brake p<3>. The switch is operated from the striker bar n. In this form the switch may be operated to stop the motor and apply the brake when the head b reaches the limit of its travel. Further movement of the striker bar in the same direction then serves to operate the reversing switch and reverse the movement. Alternatively the brake mechanism may be cut out and the head b reciprocated continuously by the switch gear. Work-positioning levers o operated against spring pressure by the tool carrier are provided. A timing device may be provided to permit the machine to make any number of strokes before coming to rest and feed mechanism may be arranged to feed the tools between successive working strokes.